Bipolar electrolytic cell

ABSTRACT

An improved bipolar diaphragm electrolytic cell assembly wherein the cell assembly is constructed of a plurality of bipole units which divide the cell into a plurality of single cells and have a structure which can be easily assembled. The connection between the anodic and cathodic portions of each bipole unit comprises a hollow partition having a current connecting plate in the hollow portion of the partition, with electroconductive bars extending from inside the pectinate anodes and cathodes to the current connection plate.

United States Patent Yoshida et al. 1 Sept. 2, 1975 54] BIPOLARELECTROLYTIC CELL 3.247.090 4/1966 Forbes 204/254 x 3,755,108 8/1973Raetzsch ct al 204/255 x Inventors: Naoshi Yoshida; Shotaro Kiga;

Takashi Yamamoto, Omiya; Kazuo Shirasaki, Yokohara, all of JapanAssignee: Nippon Soda Co., Ltd., Tokyo,

Japan Filed: Mar. 7, 1974 Appl. No.: 448,961

[30] Foreign Application Priority Data Mar. I3, 1973 Japan 48-29171 [52]US. Cl. 204/254; 204/256; 204/268; 204/286 [51] Int. Cl. C25B 13/00 [58]Field of Search 204/254, 255, 256, 268, 204/286 [56] References CitedUNITED STATES PATENTS 2,858,263 10/1958 Lucas et al. 204/256 PrimaryExaminerJohn H. Mack Assistant Examiner-W. 1. Solomon Attorney, Agent,or Firm-George B. Oujevolk [57] ABSTRACT An improved bipolar diaphragmelectrolytic cell assembly wherein the cell assembly is constructed of aplurality of bipole units which divide the cell into a plurality ofsingle cells and have a structure which can be easily assembled. Theconnection between the anodic and cathodic portions of each bipole unitcomprises a hollow partition having a current connecting plate in thehollow portion of the partition. with electroconductive bars extendingfrom inside the pectinate anodes and cathodes to the current connectionplate.

13 Claims, 17 Drawing Figures PATENT-EDSEP 2191s SHEEY PATENTED SEP 2I975 SHEET FIG-6 F/G.8

FIG]

ISJIIB i PATENTEUSEP 3, 902,984 SHEET 5 SHEET PATENTED SEP 2 75 F/G./O

EATEHTED 219.75 3,902

SHEET 7 BIPOLAR ELECTROLYTIC CELL BACKGROUND OF THE INVENTION Thepresent invention relates to a bipolar diaphragm electrolytic cellassembly and more particularly to an improved bipolar diaphragmelectrolytic cell assembly including a novel bipole unit having improvedmeans for the electrical and mechanical connection between the anodesand cathodes.

BRIEF REVIEW OF THE PRIOR ART In a bipole unit, electrodes are fixed toa partition so that the anodes of one cell may be arranged in abackto-back relationship with the cathodes of the adjacent cell and theelectrical contact may be maintained between the two.

The bipolar diaphragm electrolytic cells which are presented by Japanesepatent publication No. 5,l95 l, and Japanese patent application No.21946, 1970 have been hitherto known. The former is a typical bipolarelectrolytic cell which is well-known as the Nisso type. The latter,which was published in the bulletin of the Japan Soda IndustryAssociation Soda and Chlorine Vol. 22, No. 254, is an improvement of theformer electrolytic cell.

Both of these electrolytic cells have as one of their features thecharacteristic which is set forth in the claim of Japanese PatentPublication No. 5, I95 l, namely that the rectangular electrolytic cellis divided into a plurality of single cells by a partition arrangedperpendicularly to the major axis of the rectangular electrolytic cell.Each single cell includes many graphite anode plates fixed to thepartition in the same direction and many cathodes constructed of metalwire screen in a shape of flat bag and arranged at the side opposite tothat of the anode plates. Each cathode is fixed to a backscreen as acomblike assembly and is covered with a permeable diaphragm. Thepartition between a single cell and an adjacent single cell has a hollowpassage portion as a passage for catholyte and the anode is electricallyconnected with the cathode at said hollow portion of the partition.

On the other hand, the difference between these two cells is that theformer electrolytic cell is box-shaped and every anodes and cathodes arefixed to the partition, while the latter electrolytic cell ischannel-shaped (a shape that the opposite two side walls of the box areremoved) and the anodes and the cathodes of both ends of electrolyticcell are directly fixed to the side walls and said side walls are fixedto the electrolytic cell like a flange to form a box-shaped electrolyticcell.

The present invention further improves the latter type cell. Theelectrolytic cell of the present invention has a metal anode instead ofa graphite anode and a novel mechanical and electrical connectionbetween the electrodes.

In the above-mentioned electrolytic cell of Japanese patent applicationNo. 2I946,1970, lead welding is adopted for the mechanical andelectrical connection between the anodes and the cathodes or the mechanical connection of the anode to the anode side wall. In such anarrangement method, the anode must be fixed to the wall so that therubber lining may not be damaged by heat. While in the presentinvention. the components are secured by screws.

Thus. object of the present invention is to provide an improved bipolardiaphragm electrolytic cell which can easily be assembled anddisassembled. Another object of the invention is to provide a bipolardiaphragm electrolytic cell having improved mechanical and electricalconnections between the cathode and anode.

As used herein the term bipole unit is used to describe a bipolarassembly wherein the anodes of one cell are mounted to a partition in aback-to-baek relationship with the cathodes of an adjacent cell andelectrical contact is maintained between the two.

The partition, which serves as a supporting wall for the anodes andcathodes in the back-to-back relationship, physically separates thecells within the over-all cell housing. The term single cell is used todescribe each cell separated by the partition. The single cell includesthe anodes of one bipole unit and the cathodes of the adjacent bipoleunit. The term anode side wall" and cathode side wall are used todescribe the peripheral wall of the cell for mounting the anodes of theend single cell and the cathodes of the opposite end single cellrespectively.

Other and further objects, features and advantages of the invention willappear more fully from the following description and accompanyingdrawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I shows a plan view of theelectrolytic cell of the present invention with portions of the cellbroken away.

FIG. 2 shows a side view of the electrolytic cell with portions of thecell housing and the anode broken away.

FIG. 3 shows a plan view of the cover of the electrolytic cell.

FIG. 4 shows an elevational view of the partition with portions brokenaway.

FIG. 5 shows a longitudinal sectional view of the partition taken online 5-5 of FIG. 4.

FIG. 6 shows a side view of the anode with portions of the side of theanode broken away.

FIG. 7 shows a plan view of the anode.

FIG. 8 shows an clevational view of the anode.

FIG. 9 shows a side view of the cathode with portions of the side metalwire screen broken away.

FIG. 10 shows a plan view of the cathode assembly with portions brokenaway.

FIG. 11 shows an elevational view of the cathode assembly with portionsbroken away.

FIG. 12 shows an elevational view of the current connecting plate withportions broken away.

FIG. 13 shows a longitudinal sectional view of the current connectingplate taken on line 13-13 of FIG. 12.

FIGS. 14 and 15 show a longitudinal sectional view of the essential partof the bipole unit illustrating alternate means for mounting the anodesand cathodes to the partition.

FIG. 16 illustrates means for mounting the anodes to the anode side wallof the cell.

FIG. 17 illustrates means for mounting the cathodes to the cathode sidewall of the cell.

DETAILED DESCRIPTION FIGS. 1 and 2 show a plan view and a side view ofthe whole cell of the present invention respectively for il lustrating apreferred embodiment of the present inven tion.

The cell housing 1 is channel-shaped (a shape that the opposite two sidewalls of the box are removed and the upper side is open) and its innersurface has a suitable protective coating, such as of rubber, in orderto prevent corrosion. The cell housing 1 has guides 11 for mounting ordismounting a partition 6, openings 12 therethrough for extending theoutlet pipe 62 of the catholyte, and openings 13 for mounting theanolyte level gage. Channel-shaped cell housing 1 is connected with theanode side wall 2 and the cathode side wall 3 like a flange to form thebox-like outer shell of the cell. There is no incovenience if the cellhousing 1 is in a body with the anode side wall 2, but the cathode sidewall 3 should be removably connected to the cell housing 1 in order tobe able to remove it when renewing the diaphragm. The opening 13 may beonly one. The anode side wall 2 has a suitable protective coating, suchas of rubber, at the inner surface and has openings therethrough forextending electroconductive bars of the anode 4 outwardly. The cathodeside wall 3 also has a suitable protective coating, e.g., rubber, at theinner surface and has an inner chamber for the passage of the catholyte,a window-like opening for mounting the cathode 5, openings therethroughfor extending electroconductive bars of the cathode outwardly, ahydrogen outlet pipe 31 and a catholyte outlet pipe 32. The partition 6has a suitable protective coating, such as of rubber, at the outersurface, and has an inner chamber for the passage of the catholyte, aback plate 65 having openings therethrough for extending theelectroconductive bars of the anode, a window-like opening at the sideopposite the back plate wherein said window-like opening serves as thepassage for the catholyte, a hydrogen outlet pipe 61, and a catholyteoutlet pipe 62. The partition divides the whole cell into a plurality ofcompartments, namely, a plurality of single cells. A catholyte outletpipe 62 is removably attached to the partition and the partitionremoving said catholyte outlet pipe is vertically set to theelectrolytic cell by bringing it down along the guide 11 after both ofthe anodes and cathodes are fixed thereto. The anodes 4 and the cathodesare mounted to the anode side wall 2 and the cathode side wall 3respectively and mounted to the partition 6 in a back-to-backrelationship to form a bipole unit. When the bipolar electrolytic cellis assembled, the cathodes of one bipole unit lie between the anodes ofthe adjacent bipole unit to form a single cell. The partitions arearranged in parallel with the anode side wall and the cathode side wall.The anodes and cathodes are vertical and perpendicular to the partitionso that the surfaces of the anodes are parallel to the adjacent surfacesof the cathodes.

As mentioned above, the cell housing, anode side wall, cathode side walland the partition should have a suitable protective coating at theportions that are in contact with anolyte in order to prevent corrosion.

The bipolar cell of the present invention may be provided with only onebipole unit though a plurality of bipole units are shown in FIGS. 1 and2. The surface of the cathode is covered with a permeable diaphragm, forexample, asbestos, though it is not shown in drawings.

In the cell of the present invention, there is the slight leakage ofbrine between each adjacent single cells through a small space between apartition 6 and a guide 11, thereby providing an equal level of brine ineach single cell. During a typical operation. brine is continuouslyadded to each of the single cells through the corresponding opening 73(shown in FIG. 3). Therefore such slight leakage of brine does notinfluence the current efficiency in operation.

FIG. 3 shows a plan view of the cover of the upper side of the cell. Thecover is costrueted of iron and the inner surface has a suitableprotective coating, such as rubber, and the cover has an opening 71 forremoving chlorine, openings 72 for removing hydrogen, openings 73 forfeeding brine, an opening 74 for mounting the pressure gage of theanodic compartment and the rupture plate 75. I I

FIG. 4 shows an elevational view of the partition as seen from the sidefor mounting the cathode and FIG. 5 shows a longitudinal sectional viewof the partition 6. The partition, as partly described before, has apipe 61 for removing hydrogen, a pipe 62 for discharging the catholyte,openings 63 for mounting anodes, a backplate 65, a window-like openingwith a frame 64 around it for fixing the cathode assembly theretoclosely and a suitable protective coating at the outer surface, such asof rubber.

FIGS. 6, 7 and 8 show respectively a side view. a plan view and anelevational view of one embodiment of a metal anode employed in thepresent invention. Anode 4 includes a pair of laterally-spaced walls 41and 42. The walls 41 and 42 may be solid plate or may be of a forminousor louvered sheet materials. Anode 4 has one or more of horizontalelectroconductive bars 43 and ribs 44 between the walls 41 and 42 forsupport of the walls 41 and 42 and for electrical connection between thebar and the walls wherein said electroconductive bars are disposedbetween the walls 41 and 42. The electroconductive bar extends outwardlyfrom the end of the walls 41 and 42 and has the flange 45 at saidextending part close to the walls and further has a spiral groove 46 atthe end of the bar. Said flange 45 and said spiral groove 46 serve asmeans for mounting the anode to the partition and acurrent connectingplate. The walls 41 and 42 are preferably parallel each other.

The anode preferably includes plural electroconductive bars to fix theanode to the partition stably. The walls 41 and 42 may be constructed ofany suitable anodicallyresistant material, preferably titanium, whichsurface should be coated with a suitable anodi- Cally-resistantelectroconductive surface such as a platinum group metal or the oxide ofa platinum group metal. The electroconductive bars 43, are constructedof titanium or may be constructed of any good electroconductivematerial, such as iron, steel or copper which surface should be coatedwith titanium.

FIGS. 9, l0 and 11 show respectively a side view, a plan view and anelevational view of one embodiment of the cathode employed in thepresent invention. The cathodes 5 are constructed of metal wire screenor the like and are covered with a permeable diaphragm, for example,asbestos. The metal wire screen may be of any suitable metal, forexample iron. The cathode wall 51 takes a shape of flat bag and ishollow, in the other words, a pair of parallel side walls are joined attheir outermost ends and at their upper and lower edges thus forming achamber enclosed except for the end which opens into the chamber of thepartition. All of the cathodes in one single cell are perpendicularlyconnected to the backscreen 56 at said open ends so as to become onebody, thus forming a comb-like cathode assembly. The backscreen 56 has aperipheral flange 57 for mounting the cathode assembly closely to theframe around the window of the partition. The backscreen 56 may beconstructed of the same material as the wall 51 and should be coveredwith a permeable diaphragm as well as the wall 51. Each of the pectinatehollow cathodes has one or more of horizontal electroconductive bars 52andribs 53 for support connecting the wall 51 and for electricalconnection between the bar 52 and the wall 51, wherein said bars 52 andsaid ribs 53 are disposed in the hollow portion of the cathode. Eachcatlio preferably includes plural electroconductive bars-tcj fix thecathode-assembly to the partition stably. The electroconductive bar 52extends outwardly from the open end of the cathode and has a flange 54at said extending part close to said backscreen 56 and further has aspiral groove 55 at the end of the bar. wherein said flange 54 andspiral groove serve as means for con nectng the cathode to the currentconnecting plate.

FIGS. l2, 13 are respectively an elevational view and a longitudinalsectional view taken on line 13-13 of FIG. 12 showing a currentconnecting plate disposed at the inner chamber of the partition. Thecurrent connecting plate 8 may be of any suitable cathodicallyresistantand good electroconductive material such as iron, and has openings 81for connecting anodes and openings 82 for connecting cathodes. Thecurrent connecting plate may be one plate connected to all theelectroconductive bars of the anodes and cathodes of one bipole unit ormay be plural plate, in the other words, in case that the anode andcathode have two electroconductive bars respectively, the currentconnecting plate corresponds to a plurality of pairs ofelectroconductive bars of the anodes and cathodes, namely in this case,there are two current connecting plates.

The opening 81 and 82 should be provided on a zigzag line as shown inFIG. 12.

Referring now to FIGS. l4, I5, 16 and 17, means for mounting anodes andcathodes to a partition or a side wall is explained in detail.

FIG. 14 illustrates means for mounting anodes and cathodes to apartition and for connecting anodes to cathodes through a currentconnecting plate 8. When assembling the bipole unit shown in FIG. 14,the anodes 4 are first mounted to the partition 6 and then, the cathodesare mounted. The electroconductive bar 43 of the anode extends throughan opening 63 in the backplate 65 and is secured by binding the nut 47,wherein the backplate 65 is interposed between the flange 45 and saidnut 47. A gasket 48 should be provided between the backplate 65 and theflange 45 and a washer 49 may be provided between the backplate 65 andthe nut 47, thereby preventing any leakage between the cathodiccompartment and the anodic compartment. The gasket 48 may be anysuitable anodically-resistant material which simultaneously has goodsealing nature for liquid. The washer 49 may be a spring washer if thegasket or the coating on the partition is of the material that is apt tocause the permanent strain. All the anodes of one single cell areperpendicularly mounted to a partition, thus anodes of a bipole unittake a pectinate shape on the backplate of the partition.

Each of the electroconductive bars 52 of the pectinate cathodes extendsthrough the opening 82 in the current connecting plate 8 and is securedby binding the nut 58, wherein the current connecting plate 8 isinterposed between the flange 54 and the nut 58, thus a comb-likecathode assembly is connected to the current connecting plate 8. In thiscase, the current connecting plate may be secured to the cathodeassembly by welding instead of by screw means.

The electroconductive bar 43 of the anode, which extends through theopening 63 in the backplate 65 and is secured by the nut 47, furtherextends through an opening 81 in the current connecting plate 8 and issecured by binding the nut 410.

The cathode assembly should be designed so that the peripheral flange 57of the backscreen 56 may exactly fit the frame 64 around the window ofthe partition, otherwise undue mixing of the anolyte with the catho-Iyte may occur. The nut 410 can be operated through the opening 59 whichprovides access to said nut 410 and is disposed on the backscreen 56opposing to the connecting point of the electroconductive bar of theanode with the current connecting plate.

The opening 59 is removably covered with lid 510 which may beconstructed of the same type material as used in the backscreen of thecathode assembly or of the incorrosive material such as ebonite orpolyfluoroethylene. If the lid is constructed of metal wire screen, thelid should be covered with permeable diaphragm to surve as the cathodesurface as well as other part of metal wire screen. As means forremovably securing the lid, the lid 510 has a screw and theelectroconductive bar 43 of the anode has an opening therethrough forreception of said screw of the lid at the top of the bar 43 as shown inFIG. 14, however said means should not be limited to this.

In the bipole unit of the present invention, the pectinate anodes andcathodes are perpendicular to the partition. When the electrodes are inposition of operation, each surface of anodes is parallel with eachadjacent surface of cathodes, and a uniform and narrow space can beprovided between the anodic and cathodic surfaces.

FIG. 15 illustrates another preferred embodiment of the bipole unit ofthe present invention. In the embodiment shown in FIG. 14, opcinings foroperating the nut 410 are on the backscreen of the comb-like cathodeassembly, in the other hand, in the embodiment shown in FIG. 15,openings 66 for operating the nut 58 are on the back plate 65 of thepartition. In FIG. 15, anodes are mounted to the backplate 65 of thepartition in the same manner as in FIG. 14, however, in this embodiment,the current connecting plate 8 is secured to anodes before securing tocathodes. When assembling the bip'ole unit shown in FIG. 15, the currentconnecting plate 8 is secured to the end of the electroconductive bar 43of the anode secured to the back plate 65 by inserting the end of thebar 43 into openings 81 and se' curing with the nut 410. Then thecomb-like cathode assembly is mounted to the partition by inserting theelectroconductive bars 52 of cathodes into openings 82 and binding thenuts 58 throug openings 66. The openings 66 are disposed on the backplate 65 opposing to each connecting point of the electroconductive bars52 of the cathodes with the current connecting plate. The openings 66are covered with removable lids 67, and the lids may be constructed ofany suitable noncorrosive material, such as ebonite, polyfluoroethylene,titanium. In FIG. 15, openings 66 take the shape of nut, and lids takethe shape of bolt and are screwed in the openings, however, the meansare not limited to this. Additionally the method and structure forfixing electrodes to the partition may be the structure shown in FIG.16. The cathode including the electroconductive bar without a flange forsecuring the cathode to the current connecting plate and a spiral groovemay be employed and the electroconductive bar is secured directly to thecurrent connecting plate by welding and then, the current connectingplate is secured to the anode as mentioned before.

FIG. 16 illustrates means for mounting anodes to the anode side wall 2and for connecting anodes to the outer electric feeder plate 9. Theanode may be mounted to the anode side wall 2 in a manner identical tothe mounting of the anode to the back plate of the partition. In FIG.16, the end of the electroconductive bar 43 of the anode 4 is insertedinto the opening 21 for mounting the anode, and the anode is secured tothe anode side wall 2 by binding the nut 47, wherein the anode side wall2 is interposed between the flange 45 and the nut 47.

A gasket 48 should be provided between the flange 45 and the anode sidewall 2 and a washer 49 may be provided between the anode side wall 2 andthe nut 47. The electroconductive bar 43 of the anode is furtherconnected to the outer electric feeder plate 9 by inserting the end ofthe bar 43 into an opening in said outer electric feeder plate 9 andbinding the nut 410. The inner surface of the anode side wall 2 has asuitable protective coating 22, such as of rubber.

FIG. 17 illustrated means for mounting cathodes to the cathode side wall3 and for connecting cathodes to the outer electric feeder plate 9. InFIG. 17, the end of the electroconductive bar 52 of the cathode isinserted into the opening 33 in the backplate 36 of the cathode sidewall 3 and the cathode is secured by binding the nut 58. Gaskets 34 and35 should be provided between the flange 54 and the backplate 36 of thecath ode side wall and between the backplate 36 and the nut 58respectively, thereby preventing leakge of catholyte through opening 33.The end of the bar 52 is further inserted into the opening of the outerelectric feeder plate 9 and secured by binding the nut 511. The outersurface of the wall at the side opposite the back plate 36 has asuitable protective coating 37, such as of rubber. In the bipole unitand the cathode side wall shown in FIG. 17, each hollow portion ofcathodes communicates with the chamber being inside of the partition andthe cathode side wall through the opening end of the cathode, and formsthe cathodic compartment.

By the way, in a conventional electrolytic cell, for example the celldiscribed in Japanese patent application No. 5, 1951 or the celldescribed in Japanese patent application No. 21946, 1970, each flatbag-shaped cathode does not include the electroconductive bar, and thecurrent connecting plate is directly secured by welding to the cathodebackscreen on which each cathode is secured to form a comb-like cathodeassembly. Further, when the cathode is mounted to the cathode side wall,two or three electroconductive bars extending to the outside of the cellare connected to said current connecting plate. In such case, the partwhere the electroconductive bar is drawn out is sealed with the asbestosyarn or coal-tar.

The bipolar electrolytic cell of the present invention may seems almostthe same as the conventional one described, however, the bipolar cell ofthe present invention has the metal anode instead of graphite anode andhas the novel structure for mounting the electrodes to the partition orthe side wall and for electrical connection. According to the presentinvention, it is easy to renew a diaphragm, repair the electrodes andassemble and disassemble the cell and further, the work for assemblingand disassembling can be conducted under good environmental sanitationbecause the lead welding is not employed. In addition, the electricresistance at the electrical connecting part is sufficiently small andthe cell of the present invention can be very precisely assembled,therefore it is possible to shorten the space between the anode andcathode to operate the cell with small voltage loss, and sealing ofanolyte between each single cell is sufficiently accomplished,consequently the current efficiency is excellent.

The method of operation is the same as in a conventional diaphragmelectrolytic cell but good results are attained. The current capacity isso large as to be equal to that in mercury process cell and the floorspace of the cell of the present invention is far smaller than that ofmercury process cell and an extremely economical operation can beattained.

With regard to the efficiency, one example of the present invention isgiven:

EXAMPLE The electrolytic cell is 2050mm outer width, 3500mm length and1500mm hight and includes five compartments. Each compartment includes21 of anodes and 20 of cathodes, wherein these electrodes are 875mmhight and 570mm length.

When operating this cell under a current density of 20 A/dm", thecurrent capacity is 200 KA which corresponds to the productive capacityof caustic soda of 200 t./month, and such productive capacitycorresponds to ten-time of a conventional bipolar electrolytic cell. Thefloor space of the above-mentioned cell is 1.06 m /NaOH t /day whichcorresponds to below one-fourth of that of a conventional bipolarelectrolytic cell, therefore the routine work becomes easy and the costof the equipment becomes cheap.

The voltage loss at the current connecting parts in the bipole unit isordinarily SOmV or less. Even if the space between the anode and cathodeis 10mm, the electrodes can be easily assembled and the space can befurther shortened. The cell voltage is such low as 3.4 to 3.6 V in asingle cell. The electrolytic results such as the quality of productcannot be absolutely mentioned because they are influenced by not onlythe cell structure but also the kind of diaphragm and other conditions,however, one example of the results are mentioned for reference:current: 40KA, current capacity: 200 KA, current density: 20 A/dm cellvoltage: 3.5 V/single cell, current efficiency: 96 percent, compositionof catholyte: NaOH l40g/L, NaClO 0.2g/L, composition of anode gas: C198.5%, CO 0.2%, 0 0.6% H 0. 1%.

As above mentioned, the bipolar electrolytic cell of the presentinvention is the epochal cell which surpasses the conventional diaphragmelectrolytic cell.

As many apparently widely different embodiments of the present inventionmay be made without departing from the spirit and scope thereof, it isto be understood that the invention is not limited to the specificembodiments thereof except as defined in the appended claims.

What is claimed is:

l. A bipolar diaphragm electrolytic cell assembly, divided into aplurality of single cells as a plurality of bipole units, each of saidbipole units having elongated comb-like anodes and cathodes (4,including pectinate anode and cathode hollow portions, a diaphragm onsaid cathodes, a backscreen (56) having openings, on which said cathodesare connected, a partition (6) with hollow portions having a backplate(65) with openings (63) for securing said anodes, a window (64) forsecuring said cathode opposite said backplate (65) forming cathodiccompartments by combining the hollow portions of said cathodes and saidpartition, further comprising:

a. an electrode securing means including one or more electroconductivebars (43, 52) disposed in said hollow portions of each anode and eachcathode and extending to said partition hollow portion;

b. one or more current connecting plates (8) having connecting openings(81, 82) for connecting to the electroconductive bars of the anodes andcathodes, disposed in said partition hollow portion of each bipole unit,said electroconductive bars (43, 52) of the anodes and cathodes beingelectrically interconnected to said connecting openings (81, 82) of saidcurrent connecting plates, each of said connecting anode openings (81)being so situated as to be opposite to the backscreen (56) betweenadjacent cathodes;

c. said electroconductive bars of said anodes having a flange (45) formounting to the back plate (65) and extending through said opening inthe backplate and the opening in the current connecting plate (8);

d. said electroconductive bars of said cathodes having a flange (54) formounting to the backscreen (56) and extending through said opening inthe backscreen and the opening in the current connecting plate (8); and,

e. screw means (47, 58) securing said electroconductive bars of saidanodes to said backplate and connecting plate, and securing saidelectroconductive bars of said cathodes to said backscreen and connecting plate.

2. The bipolar diaphragm electrolytic cell defined in claim 1 whereinsaid screw means securing said electroconductive bars of said anodescomprises nuts and a spiral groove provided to the electroconductive barof the anode.

3. The bipolar diaphragm electrolytic cell defined in claim 2 whereinthe backscreen has openings with removably attached lids, each of saidopenings with removably attached lids providing access to said nut andbeing disposed at the point opposite the connecting opening of thecurrent connecting plate for the electroconductive bar of the anode.

4. The bipolar diaphragm electrolytic cell defined in claim 3 whereinsaid lid has a screw and the electroconductive bar of the anode has anopening therethrough for reception of said screw at the top thereof.

5. The bipolar diaphragm electrolytic cell defined in claim 1 whereinsaid screw means securing said electroconductive bars of said cathodescomprises a nut and a spiral groove provided to the electroconductivebar of the cathode.

6. The bipolar diaphragm electrolytic cell defined in claim 5 whereinthe backplate has openings with removably attached lids, each of saidopenings with removably attached lids providing access to said nut andbeing disposed at the point opposite the connecting opening of thecurrent connecting plate with the electroconductive bar of the cathode.

7. The bipolar diaphragm electrolytic cell defined in claim 1 whereinthe cell housing is channel-shaped, and the anode side wall and thecathode side wall are connected to said cell housing like a flange toform a boxlike outer shell of the cell.

8. The bipolar diaphragm electrolytic cell defined in claim 7 whereinsaid cell housing includes guides for vertically mounting and removingthe bipole units.

9. The bipolar diaphragm electrolytic cell defined in claim 1 whereinthe anodes and cathodes are perpendicular to said partition, and thesurfaces of anode are parallel with the opposing surfaces of cathode.

10. A bipolar diaphragm electrolytic cell for electrolytic decompositionof chlor-alkali divided into a plurality of single cells by pluralbipole units, each of said bipole units having an elongated comb-likecathode assembly which includes pectinate hollow cathodes and abackscreen to which said cathodes are connected, a diaphragm on saidcathodes, elongated pectinate hollow anodes and a hollow partition whichhas a backplate having openings for fixing said anodes and a window forfixing said cathode assembly at the side opposite said backplate, thecathodic compartments being formed by combining the hollow portions ofsaid cathodes and said partition, which comprises one or moreelectroconductive bars disposed in said hollow portions of said anodeand each cathode respectively and extending to said hollow portion ofthe partition, and one or more current connecting plates connectedmechanically and electrically to said electroconductive bars of cathodesand disposed in said hollow portion of the partition of each bipoleunit, said current connecting plate having openings for connecting tothe electroconductive bars of the anodes, each of said electroconductivebars of the anodes having a flange for mounting on the backplate and athreaded end and extending through the opening in the backplate and theopening in the current connecting plate and being secured by nuts, thenuts interleaving with the current connecting plate, said backscreenhaving openings with removably attached lids, each of said openings inthe backscreen providing access to a nut disposed at the backscreen sideof the current connecting plate and being disposed at the point oppositethe connecting point of the current connecting plate with theelectroconductive bar of the anode.

l l. The bipolar diaphragm electrolytic cell defined in claim 10 whereinsaid current connecting plate has openings for connecting to theelectroconductive bars of the cathodes, and each of saidelectroconductive bars of the cathodes has a flange for securing to thecurrent connecting plate and a threaded end and extends through saidopening in the current connecting plate and is secured by a nut whereinthe backplate has openings with removably attached lids, each of saidopenings with removably attached lids being disposed at the pointopposite the connecting point of the current connecting plate with theelectroconductive bar of the cathode and providing access to said nutsecured to the electroconductive bar of the cathode.

12. The bipolar diaphragm electrolytic diaphragm cell defined in claim10 wherein the cell housing is channel-shaped and the anode side walland the cathode side wall are connected to said cell housing like achannebshaped, and the anode side wall and the cathflange to form abox-like outer shell of the cell. ode side wall are connected to saidcell housing like a 13. The bipolar diaphragm electrolytic diaphragmflange to form a box-like outer shell of the cell.

cell defined in claim wherein the cell housing is

1. A BIPOLAR DIAPHRAM ELECTROLYTIC CELL ASSEMBLY, DIVIDED INTO APLRALITY OF SINGLE CELLS AS A PLURALITY OF BPOLE UNITS EA CH OF SAIDBIPOLE UNITS HAVING ELONGATED COMB-LIKE ANODES AND CATHODES (4,5)INCLUDING PECTINATE ANODE AND CATHODE HOLLOW PORTIONS, A DIAPHRAM ONSAID CATHODES, A BACKSCREEN (56) HAVING OPENINGS, ON WHICH SAID CATHODESARE CONNECTED, A PARTITION (6) WITH HOLLOW PORTIONS HAVING A BACKPLATE(65) WITH OPENINGS (63) FOR SECURING SAID ANODES, A WINDOW (64) FORSECURING SAID CATHODE OPPOSITE SAID BACKPLATE (65) FROM ING CATHODICCOMPARTMENTS BY COMBINING THE HOLLOW PORTIONS OF SAID CATHODES AND SAIDPARTITION, FURTHER COMPRISING: A. AN ELECTRODE SECURING MEANS INCLUDINGONE OR MORE ELECTROCONDUCTIVE BARS (43), 52) DISPOSED IN SAID HOLLOWPORTIONS OF EACH ANODE AND EACH CATHODE AND EXTENDING TO SAID PARTITIONHOLLOW PORTION, B. ONE OR MORE CURRENT CONNECTING PLATES (8) HAVINGCONNECTING OPENINGS (81, 82) FOR CONNECTING TO THE ELCTROCONDUCTIVE BARSOF THE ANODES AND CATHODES, DISPOSED IN SAID PARTITION HOLLOW PORTION OFEACH BIPOLE UNIT, SAID ELECTROCONDUCTIVE BARS (43, 52) OF THE ANODES ANDCATODES BEING ELECTRICALLY INTERCONNECTED TO SAID CONNECTING OPENINGS(81,82) OF SAID CURRENT CONNECTING PLATES, EACH OF SAID CONNECTING ANODEOPENINGS (81) BEING S SITUATED AS TO BE OPPOSITE TO THE BACKSCREEN (56)BETWEEN ADJACENT CATHODES, C. SAID ELECTROCONDUCTIVE BARS OF SAID ANODESHAVING A FLANGE (45) FOR MOUNTING TO THE BACK PLATE (65 AN EXTENDINGTHROUGH SAID OPENING IN THE BACKPLATE AND THE OPENING IN THE CURRENTCONNECTING PLATE (8), D. SAID ELETROCONDUCTIVE BARS OF SAID CATHODESHAVING A FLANGE (54) FOR MOUNTING TO THE BACKSCREEN (56) AND EXTENDINGTHROUGH SAID OPENING IN THE BACKSCREEN AND THE OPENING IN THE CURRENTCONNECTING PLATE (8), AND, E. SCREW MEANS (47,58) SECURING SAIDELECTROCONDUCTIVE BARS OF SAID ANODES TO SAID BACKPLATE AND CONNECTINGPLATE, AND SECURING SID ELECTRCONDUCTIVE BARS OF SAID CATHODES TO SAIDBACKSCREEN AND CONNECTING PLATE.
 2. The bipolar diaphragm electrolyticcell defined in claim 1 wherein said screw means securing saidelectroconductive bars of said anodes comprises nuts and a spiral grooveprovided to the electroconductive bar of the anode.
 3. The bipolardiaphragm electrolytic cell defined in claim 2 wherein the backscreenhas openings with removably attached lids, each of said openings withremovably attached lids providing access to said nut and being disposedat the point opposite the connecting opening of the current connectingplate for the electroconductive bar of the anode.
 4. The bipolardiaphragm electrolytic cell defined in claim 3 wherein said lid has ascrew and the electroconductive bar of the anode has an openingtherethrough for reception of said screw at the top thereof.
 5. Thebipolar diaphragm electrolytic cell defined in claim 1 wherein saidscrew means securing said electroconductive bars of said cathodescomprises a nut and a spiral groove provided to the electroconductivebar of the cathode.
 6. The bipolar diaphragm electrolytic cell definedin claim 5 wherein the backplate has openings with removably attachedlids, each of said openings with removably attached lids providingaccess to said nut and being disposed at the point opposite theconnecting opening of the current connecting plate with theelectroconductive bar of the cathode.
 7. The bipolar diaphragmelectrolytic cell defined in claim 1 wherein the cell housing ischannel-shaped, aNd the anode side wall and the cathode side wall areconnected to said cell housing like a flange to form a box-like outershell of the cell.
 8. The bipolar diaphragm electrolytic cell defined inclaim 7 wherein said cell housing includes guides for verticallymounting and removing the bipole units.
 9. The bipolar diaphragmelectrolytic cell defined in claim 1 wherein the anodes and cathodes areperpendicular to said partition, and the surfaces of anode are parallelwith the opposing surfaces of cathode.
 10. A bipolar diaphragmelectrolytic cell for electrolytic decomposition of chlor-alkali dividedinto a plurality of single cells by plural bipole units, each of saidbipole units having an elongated comb-like cathode assembly whichincludes pectinate hollow cathodes and a backscreen to which saidcathodes are connected, a diaphragm on said cathodes, elongatedpectinate hollow anodes and a hollow partition which has a backplatehaving openings for fixing said anodes and a window for fixing saidcathode assembly at the side opposite said backplate, the cathodiccompartments being formed by combining the hollow portions of saidcathodes and said partition, which comprises one or moreelectroconductive bars disposed in said hollow portions of said anodeand each cathode respectively and extending to said hollow portion ofthe partition, and one or more current connecting plates connectedmechanically and electrically to said electroconductive bars of cathodesand disposed in said hollow portion of the partition of each bipoleunit, said current connecting plate having openings for connecting tothe electroconductive bars of the anodes, each of said electroconductivebars of the anodes having a flange for mounting on the backplate and athreaded end and extending through the opening in the backplate and theopening in the current connecting plate and being secured by nuts, thenuts interleaving with the current connecting plate, said backscreenhaving openings with removably attached lids, each of said openings inthe backscreen providing access to a nut disposed at the backscreen sideof the current connecting plate and being disposed at the point oppositethe connecting point of the current connecting plate with theelectroconductive bar of the anode.
 11. The bipolar diaphragmelectrolytic cell defined in claim 10 wherein said current connectingplate has openings for connecting to the electroconductive bars of thecathodes, and each of said electroconductive bars of the cathodes has aflange for securing to the current connecting plate and a threaded endand extends through said opening in the current connecting plate and issecured by a nut wherein the backplate has openings with removablyattached lids, each of said openings with removably attached lids beingdisposed at the point opposite the connecting point of the currentconnecting plate with the electroconductive bar of the cathode andproviding access to said nut secured to the electroconductive bar of thecathode.
 12. The bipolar diaphragm electrolytic diaphragm cell definedin claim 10 wherein the cell housing is channel-shaped and the anodeside wall and the cathode side wall are connected to said cell housinglike a flange to form a box-like outer shell of the cell.
 13. Thebipolar diaphragm electrolytic diaphragm cell defined in claim 10wherein the cell housing is channel-shaped, and the anode side wall andthe cathode side wall are connected to said cell housing like a flangeto form a box-like outer shell of the cell.